The present invention relates to a guide bar for saw chains of a motor chain saw with an outer peripheral guide groove which is engaged by the central drive members of the saw chain, with a race formed by each shoulder of the guide groove on which the lateral connecting members connecting the drive members of the saw chain run, whereby the shoulders at least over a portion of their peripheral length are covered by an attached wear protector which is made of a material which is more wear resistant then the material of the guide bar member of the guide bar.
Such a guide bar is known from U.S. Pat. No. 3,858,321. For protecting against increased wear the reversal area of the guide bar is provided with a wear protecting portion applied to the stays of the guide groove which wear protecting parts are fixedly connected to the stays, for example, by welding or brazing The wear protecting part is comprised of a material that is more wear-resistant than the guide bar member of the guide bar. Suitable for this purpose are, for example, cobalt hard alloys (stellite).
However, in practice it has been proven that after a certain operating period the material of the wear protectors due to the load exerted thereon is plastically deformed. It has been found especially that the material of the wear protecting parts grows into the guide groove and thus makes it more narrow. This results in the saw chain moving with difficulty within the guide groove so that an increased amount of drive power is required for driving the saw chain which is thus no longer available for the cutting action of the saw chain. Under unfavorable conditions the deformation (growing) of the material of the wear protecting parts into the guide groove can result in jamming of the saw chain and thus to failure of the motor chain saw. It is therefore an object of the present invention to improve a guide bar of a saw chain of a motor chain saw such that even after prolonged operation a narrowing of the guide groove can be reliably prevented.